The term PIN feather is what is commonly used. I suppose the concept being that the tip of the feather (feathers are made of keratin protein), encased in a waxy casing, "pokes" (like a pin would) or fledges thru the hole for the feather (feather follicle) from where the original feather that is being replaced was originally.

I have had turkey hens moult so quickly she never had much time to break the waxy casing preening with her beak. She would ruffle what should be her feathers and make rattling noises! I called this stage, her "Porcupine" stage. Turkeys can be strange birds to begin with...ones encased in greyish pins instead of feathers are even stranger!

Some refer to PIN feathers as BLOOD feathers but as Wikipedia points out below...that term is only good so long as the blood is flowing WITHIN the feather as it develops.

The quote below will also answer your query about what the names of the parts are when the PIN feather opens up. I believe the specific parts are the barbs, barbules (feather webs) and central shaft or as more commonly called "quill."

Three types of feathers being vaned, down, and filoplume.

The feather shaft (rachis) becomes the quill (hollow tubular calamus) and fused to the main shaft are the barbs and branched further into barbules.

Pin featherA pin feather, sometimes called a "blood feather", is a developing feather on a bird. This feather can grow as a new feather during the bird's infancy, or grow to replace one from moulting.

The pin feather looks somewhat like a feather shaft. However, unlike a fully developed feather, the pin feather has a blood supply flowing through it. As such, if the pin feather is damaged, a bird can bleed heavily.

As the pin feather grows longer, the blood supply is concentrated in only the base of the shaft, and the tip of the shaft encases the feather itself, in a waxy coating. As moulting birds preen, they remove the waxy coating, and the feather unfurls.

When the blood has receded, the term "blood feather" is no longer synonymous with "pin feather" – it can only be referred to as a pin feather.

GrowthPin feathers begin to develop after the feather bud invaginates a cylinder of epidermal tissue around the base of the dermal papilla, forming the feather follicle. At the base of the feather follicle, epithelial cells proliferate to grow the epidermal collar or cylinder. As the epidermal cylinder extends through dermis, it differentiates into a protective peripheral sheath, longitudinal barb ridges, and growth plates. Over time these barb ridges lengthen helically, branch to create barbs and barbules, and fuse to form the rachis or central shaft. Moreover, the barb plate further differentiate into hooklets and cilia, while the marginal and axial plate die to form the intervening space within the feather structure.

Always an immense pleasure when the opportunity arises that we may actually assist persons of your high standing in the Fancy.

I'll never catch up to the help you have so generously given me and others here...but we CAN keep trying to challenge the overall tally's total on who gives more good help than the other! Heh heh heh...keep in mind I said "TRY!"

I hope I will be capable of explaining what my "problem" is. According to the paper the Cp gene is actually the absence(deletion) of the ENTIRE IHH gene (Indian Hedgehog). Personally I can live with it, but I'd feel awkward while explaining to others, that the gene is actually the absence of the gene. Is there any definition of a gene, that covers such a situation?Similar case with the Fm gene. According to what have been written, a region of a chromosome containing whole 5 genes is duplicated, and both copies of the original eumelanizing gene are expressed.

Not only are there deletions, duplications etc of a gene, but also mutations in non-coding DNA regions, partial modification of multiple genes (eg K mutation) & even just deletions upstream to the structural gene, not on the gene itself (eg ASIP - agouti yellow in Jap Quails, SOX10 - Db in chickens, etc).------------------------

6.3 LocusA locus is a point in the genome, identified by a marker, which can be mapped by some means. It does not necessarily correspond to a gene; it could, for example, be an anonymous non-coding DNA segment or a cytogenetic feature. A single gene may have several loci within it (each defined by different markers) and these markers may be separated in genetic or physical mapping experiments. In such cases, it is useful to define these different loci, but normally the gene name should be used to designate the gene itself, as this usually will convey the most information.

Also from the mouse genetics website:

Quote:

A single chromosome can only carry a single allele and, except in cases of duplication, deletion or trisomy, an animal carries two autosomal alleles. In particular, a transgene inserted randomly in the genome is not an allele of the endogenous locus; the condition is termed hemizygous if the transgene is present only in one of the two parental chromosome sets. By contrast, a gene modified by targeting at the endogenous locus is an allele and should be named as such.

*need to copy & paste above URL into browser----------------------------Using the above mouse genetics nomenclature rules, the old Fm nomenclature could be expressed as EDN3Fm for the Fibromelanosis mutation, and EDN3+ for the wild-type. Ie once the structural gene is identified, you combine old allele symbols with the structural gene.Therefore, you wouldn't do EDN3FmFm for the Fibromelanosis allele, as "Fm" defines all the sequence for the Fibromelanosis mutation. You don't use the old allele nomenclature to express structural gene duplications & other modifications. Also it wouldn't be accurate to leave out other structural genes within the duplicated region.

I hope I will be capable of explaining what my "problem" is. According to the paper the Cp gene is actually the absence(deletion) of the ENTIRE IHH gene (Indian Hedgehog). Personally I can live with it, but I'd feel awkward while explaining to others, that the gene is actually the absence of the gene. Is there any definition of a gene, that covers such a situation?Similar case with the Fm gene. According to what have been written, a region of a chromosome containing whole 5 genes is duplicated, and both copies of the original eumelanizing gene are expressed.

So with the above mouse genetics website definitions, the locus covers all the genomic regions modified in a mutation allele, & is not limited to a single structural gene. Nor is it limited to coding regions of a gene. But they usually name the locus allele after the structural gene that's expression is modified.

So the deletion of the genomic region in which the IHH gene is usually found, of course then knocks out expression of the IHH gene, therefore they say that Cp is a mutation of the IHH locus. Similar with Fm and EDN3 locus. The Fm allele has much more modification to this genomic region than the EDN3 structural gene itself, but it has the most effect on the expression of the EDN3 gene, therefore is named after it.

They also mention in that Cp paper that in humans a deletion of an amino acid in the IHH gene is causal to brachydactyly. As IHH is right next to the Rosecomb locus in chickens, I'm wondering now about the high incidence of brachydactyly I had in crosses of non-brachydactyly feather-legged single comb d'Uccles & non-brachydactyly clean-legged rosecomb Sebrights. I wish I had taken note of any correlations/linkages between rosecomb & brachydactyly, with feather-legged. Who knows, brachydactyly in chickens may be a mutation of IHH too (or a modifier/suppressor of brachydactyly expression), or in the same region (but possibly needing feather-legged genes for expression?).

In the pigeon feather-legged (ptilopody) study, their candidate genes (including a possible chicken one) were on chromosomes 13 & 15 in chickens, but Creeper & Rosecomb are on chromosome 7. But then, brachydactyly is not expressed in all chickens with feather legs (although brachydactyly rare when clean-legged).